Fuel injection pump



April 22, 1952 N. FODOR 2,595,551

FUEL INJECTION PUMP Filed Dec. 8, 1947 2 SHEETS-SHEET 1 I i J 22 i 22 gO i f! I I U 23 o *J 14 II' I' I I; Ii

c? G JNVENTOR.

S MC/ZOZQS ibczaf, 15-; BY

April 22, 1952 N. FODOR 2,593,551

FUEL INJECTION PUMP Filed Dec. 8, 1947 2 SHEETS-SHEET 2 1 1/ 12 Nun-3%:w u lllllll i; 6

Patented Apr. 22, 1952 UNITED STATES PATENT OFFICE 5. Clai Thisinvention has to do with fuel injectionpumps, and is particularlyconcerned with an improved pump of the type in which the quantity of;fuel delivered by the (pump during each injection controlled at theinlet of the :pump. Although capable, of being used for other purposesthe newpump is particularly well suited for use in connection withDiesel engines.

The principal object of the invention is to provide an improved pump ofthe character described having simple yeteiiective means for bypassingexcess fuel back into the fuel supply chamber ofthe pump withoutcreating ob-j ectionable turbulence therein.

Otherobjects and advantages of the invention will, be apparent tothoseskilled in the art upon a full understanding of the construction,arrangement and operation of the parts entering into theconstruction ofthe improved pump.

A preferred embodiment of the invention is presented herein for thepurpose of exemplification but it will of course be appreciated that theinvention is susceptible of incorporation in other structurally modifiedforms coming equally within the scope of the appendedclaims.

In the accompanying drawings:

Fig. 1 is aside view of a fuel injection pump which has incorporatedtherein theimproyement constitutingthe present invention;

Fig. 2 is a different side view of the pump;

Fig. 3 is a plan view of the pump;

Fig. 4 is a vertical section throughthe pump, taken on approximately thelined-4 of Fig. 1

Fig. 5 is another vertical section, taken on approximately the line.55of Fig. 2; and

Fig. 6 is a horizontal section, taken on approximately the line 6.B ofFig. 4.

Referring in more detail to the drawingsit will be observed that thepump is characterized by a body III which is adapted to be bolted orotherwise securely fastened to the associated engine. The body I isprovided with a vertical bore and: horizontal bore, l2. Theuppercentralportion of the bore ll constitutes, the pumpingchamb'er, whilethebore. l2 constitutes the fuel inlet chamber.

A plunger l3 reciprocates vertically with a constant length strokewithinthe bore I I in freely slidable but fluid-tight engagement with thesame. The plunger I3 is moved upwardly by a cam M on the cam shaft ofthe associated engine and is moved downwardly by a coil spring l6 whichis compressed between the underside of the body l0 and a spring seat I1secured to the lower exposed end N3 of the plunger.

The plunger 13 is provided a predetermined distance below its upper endwith an annular groove l9, and the groove I9 is connected to the pumpingchamber space above the plunger by radial passages 20 in the bottom ofthe groove which communicate with a centrally arranged upwardly openingbore 2| in the upper end of the plunger.

The upper end of the, bore l l is closed oil by a delivery valveassembly 22, which assembly includes, a delivery union 23 which isadapted tobeconnected by suitable tubing withthe injector, an annularvalve, seat 24 at the lower end of the union, a vertically movablervalve25 on the seat,

anda small coil spring 26 for pressing, the valve downwardlyagainst theseat. I

The bore l2, whichconstitutes; the-fuel supply chamber, is adapted to beconnected at one end with the fuel supply line 21 and isada pted to beclosed at its other end by a screw plug 28, either end of the bore I2being optionally connectable with the fuel supply line.

A fuel quantity control shaft 29 is rotatably mountedin a horizontalposition in the body 10, with its center portion as passing crosswisethrough and exposed within the bore I2, and with its end portions 3| and32 journalled respectively in aligned bores 33 and 34 in freelyrotatable, but fluid-tight engagement with the latter. Onelend of theshaft 29 projects from the body In and is provided with a lever 35 bymeans of which the shaft is adapted to be turned through a predeterminedangle.

The portion 30 of theshaft 29 which is exposed;

within the bore I2 is provided withradial pasedges; 36 which open into alongitudinal extending bore; 3] in the shaft. The bore-31 isvclosedatits far end byascrew plus 38 and is connected with a radial passage 39which; opensinto anec centrically formed arcuate roove, 40 in the outersurfaceof the shaft. The, groove-40 isformed in that portion of theshaft 291 which isjournalled; withinthe bore, 34, and is-located atapointdia Thenbore-3'4 is conrectly-oipposite the bore H. nected with thebore II at the. location-ofthegroove. 40 by; an inletzport-A I, whichport. opens;- into the-"pumping chamberportion of the borel IE justabovethe edgeofr-theltop 4210f thenplunger;

I 3'; when thelatter isin' its. lowermost: position;

Below the inlet port 4| the bore ll connects again with the bore I 2 bya spill port 43-, which port is adapted to communicate with the annulargroove l9 in the plunger I3 at a predetermined point in the upwardtravel of the plunger, whereby to by-pass fuel back into the bore [2.

The improvement which constitutes the presnt invention is the provisionin the bore l2 of a special spill deflecting element 44, which elementmay advantageously consist of a pin 45 which is press fitted orotherwise securely held within a bore 46 in the body It with its axisaligned with the spill port 43 and with its confronting end 41 abruptlyformed at right angles to the axis of the spill port. The pin 45 ispreferably somewhat larger in diameter than the spill port 43 and islocated in direct opposition and in close proximity to the latter. Thepin is preferably spaced about of an inch from the discharge end of thespill port, but this spacing may be increased or decreased and yetafford the desired-baffling effect on the fuel.

The pump operates as follows: In the lowermost position of the plungerl3 (which is the position shown in Figs. 4 and 5) fuel from the bore l2flows through the inlet port 4| into the bore II across the top 42 ofthe plunger, metered by the restriction determined by the angularposition of the fuel quantity control shaft 29. As the plunger l3 movesupwardly in the bore H the top 42 of the plunger cuts off the inlet port4!, after which the fuel trapped in the bore H above the plunger isforced upwardly past the delivery valve 25 and through the tube leadingto the injector. As soon as the plunger H5 in its upward movementreaches a position wherein the groove 19 uncovers the spill port 43delivery of fuel through the valve 35 abruptly ceases and that fuelwhich is displaced by the movement of the plunger during the remainderof its upward movement is by-passed through the spill port 43 back intothe bore l2.

As the fuel is discharged from the spill port 43 back into the bore [2it impinges. squarely against the plug-like end 41 of the bafflingelement 44 immediately upon entering the bore and has its dynamic energyquickly and effectively dissipated. This dissipation, by the meansherein disclosed, has been found to materially improve the operation ofa pump of this type, preventing pressure waves in the fuel frompenetrating into the bore I2 to such extent as to cause therein unwantedmomentary increases in the pressure and violent motion of the fuel.

I claim:

1. In a fuel injection pump, a pumping chamber, a constant strokeplunger reciprocally mounted therein, said plunger having acircumferentially continuous head which closely fits the pumping chamberand terminates at its lower end in a laterally opening recess, whichrecess communicates through the head with an upwardly opening recess inthe top of the latter, an outlet port from the upper end of the pump ingchamber adapted for connection with an injector, a fuel chamber for bothsupplying fuel to the pumping chamber and receiving excess fuel fromthat chamber, a single inlet port into the pumping chamber from the fuelchamber, which port is located just above the top of the head of theplunger in the lowermost position of the latter, an adjustable meteringvalve located between the fuel chamber and the inlet port for variablycontrolling the rate of flow of the fuel from the fuel chamber throughsaid inlet port into the pumping chamber, a single spill port from thepumping chamber into the fuel chamber, which port is located asubstantial distance below the inlet port and is closed off from thepumping chamber by the head of the plunger in the lowermost position ofthe plunger, being placed in communication with the pumping chamber bysaid laterally opening recess only after the piston has moved upwardly apredetermined distance, and a baiile member located in the fuel chamberadjacent to but spaced from the discharge end of the spill port, in aposition in direct opposition thereto, for reducing in the fuel presentin the fuel chamber the turbulence which would otherwise be caused bythe fuel returned to the fuel chamber through the spill port, withoutobstructing such return.

2. A fuel injection pump of the construction set forth in claim 1,wherein the baffle member is so arranged as to afford a substantiallyflat right angular impingement surface for the fuel entering the fuelchamber from the spill port.

3. A fuel injection pump of the construction set forth in claim 1,wherein the baffle member is structurally separate from the fuel chamberand is capable of being adjusted toward or away from the discharge endof the spill port.

4. A fuel injection pump of the construction set forth in claim 1,wherein the bailie member consists of a pin which is secured in a borein the fuel chamber in substantially axial registration with the spillport and terminates in a substantially fiat end face, which end face isspaced but a small fraction of its diameter from the end of the spillport.

5. A fuel injection pump of the construction set forth in claim 1,wherein the fuel chamber consists of a short bore in right angularlaterally spaced relation to the pumping chamber, the adjustablemetering valve includes a rotatable operating stem which extendscrosswise through said bore and is provided with a longitudinallyextending fuel passage which opens radially at one end intocommunication with said bore and at the other end into communicationwith the fuel chamber, and the baffle member consists of a pin whichextends crosswise of said bore in closely spaced relation to said stemand in substantially axial registration with the spill port andterminates in an end face which is spaced but a small fraction of itsdiameter from the end of the spill port.

NICHOLAS FODOR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,130,521 Brunner Sept. 20, 19382,309,074 Edwards Jan. 19, 1943 FOREIGN PATENTS 7 Number Country Date665,885 Germany 1938

